Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M39/00—Arrangements of fuel-injection apparatus with respect to engines; Pump drives adapted to such arrangements
  • F02M39/005—Arrangements of fuel feed-pumps with respect to fuel injection apparatus
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00

Definitions

• the present invention relates to a pump unit for a fuel injection system of an internal combustion engine.
• the present invention relates to a pump unit for a fuel injection system of an internal combustion engine, in which the pump unit is arranged along the fuel feed circuit and comprises a high-pressure pump and a pump for pre-feeding the high-pressure pump.
• the high-pressure pump comprises a pump body and a flange joined to the pump body.
• the feed circuit comprises a feed branch and a delivery branch of the pre-feed pump, a fuel tank and a fuel filter.
• the feed branch connects a tank to the pre- feed pump, while the delivery branch connects the pre-feed pump to the high- pressure pump.
• the fuel filter is arranged along the feed branch or along the delivery branch.
• the feed circuit comprises a bypass branch which directly connects the feed branch and the delivery branch so as to bypass the pre-feed pump, and an overpressure valve which is arranged along the bypass circuit so as to allow discharge into the feed branch of any overpressure prevailing along the delivery branch so as to avoid damaging the fuel filter.
• the pre-feed pump does not require the bypass circuit and the associated overpressure valve.
• the delivery branch, the feed branch and the bypass branch, where present, are formed at least partly inside the pre-feed pump.
• each pre-feed pump model with given delivery characteristics must be manufactured with at least two variants in order to meet the requirements of the various car manufacturing companies.
• the object of the present invention is to provide a pump unit of the type described above able to overcome the drawbacks of the prior art.
• a pump unit for a fuel injection system of an internal combustion engine in which the pump unit is arranged along the fuel feed circuit and comprises a pre-feed pump and a high- pressure pump which comprises a pump body and a flange joined to the pump body, the feed circuit comprising a feed branch and a delivery branch of the pre- feed pump, the pump unit being characterized in that the feed branch and the delivery branch of the pre-feed pump are formed, at least partly, in the flange of the high-pressure pump.
• the various variants of the feed circuit may be formed in the flange which, in the case in question, is a less complex component of the pre-feed pump and may be easily produced with different variants for each model of the pump unit, thereby greatly reducing the disadvantages of the prior art.
• FIG. 1 is a schematic view, with parts removed for the sake of clarity, of a fuel injection system for an internal combustion engine, comprising a pump unit designed according to the present invention
• FIG. 2 is a side elevation view, with parts removed for the sake of clarity and on a larger scale, of a detail of the pre-feed pump according to Figure 1.
• FIG 1, 1 denotes generally in its entirety a fuel injection system of an internal combustion engine.
• the injection system 1 comprises a circuit 2 for feeding the fuel to an internal combustion engine (not shown in the accompanying figures) and a pump unit 3 comprising a pre-feed pump 4 and a high-pressure pump 5 for feeding a common rail (not shown in the accompanying figures).
• the injection system 1 comprises in succession a tank 6, a pre-filter 7 for separating the water from the intake fuel, the pre-feed pump 4 and the high- pressure pump 5, and a fuel filter 8.
• the circuit 2 comprises a feed branch 9 which connects the tank 6 to the pre- feed pump 4 and a delivery branch 10 which connects the pre-feed pump 4 to the high-pressure pump 5.
• the pre-filter 7 is arranged along the intake branch 9 between the tank 6 and the pre-feed pump 4, while the filter 8 is arranged along the delivery branch 10.
• the circuit 2 comprises a high-pressure delivery branch 11 which connects the high-pressure pump 5 to the common rail (not shown in the accompanying figures) and a choke 12 arranged along the feed branch 9 downstream of the pre-filter 7.
• the feed branch 9 can be connected to a manual pump 13 which has the function of filling the circuit 2 of the injection system 1 with fuel without starting the pre-feed pump 4 and the high-pressure pump 5.
• the pre-feed pump 4 comprises a pump body 14 and a pumping station 15 housed inside the pump body 14.
• the high-pressure pump 5 comprises a pump body 16, a pumping station 17 housed inside the pump body 16, a flange 18 joined to the pump body 16 and a shaft 19 which is schematically indicated by means of a dot-dash line and has the function of operating the pumping station 17 and the pumping station 15.
• the pump body 14 is joined to the pump body 16 on the opposite side of the flange 18.
• the circuit 2 comprises a bypass branch 20 which comprises two parallel branches 21 and 22 arranged in parallel and connects the feed branch 9 to the delivery branch 10 and is arranged in the flange 18 in parallel with the pumping station 15, an overpressure valve 23 arranged along the branch 21, and a bypass valve 24 arranged along the branch 22 in parallel with the overpressure valve 23 and the pumping station 15.
• a bypass branch 20 which comprises two parallel branches 21 and 22 arranged in parallel and connects the feed branch 9 to the delivery branch 10 and is arranged in the flange 18 in parallel with the pumping station 15, an overpressure valve 23 arranged along the branch 21, and a bypass valve 24 arranged along the branch 22 in parallel with the overpressure valve 23 and the pumping station 15.
• the overpressure valve 23 is calibrated so as to discharge, along the feed branch 9, the excess fuel pumped by the pre-feed pump 4, namely when the fuel pressure in the delivery branch 10 exceeds a given value, for example a value in the region of 10 bar.
• the bypass valve 24 is calibrated so as to bypass the pumping station 15 when the fuel pressure in the delivery branch 9 assumes a given value during preparation of the injection system 1 for initial use.
• the feed branch 9 is fed by the manual pump 13 which has the function of filling the circuit 2 of the injection system 1 without starting the pre- feed pump 4 and the high-pressure pump 5.
• part of the feed branch 9, part of the delivery branch 10 and the whole of the bypass branch 20 including the overpressure valve 23 and the bypass valve 24 are arranged in the pump unit 3.
• the feed branch 9 and the delivery branch 10 extend along the whole of the pump unit 3 and pass through the flange 18, the pump body 16 and the pump body 14.
• the delivery branch 10 after passing through the filter 8, again passes through the flange 18 and the pump body 16 so as to feed the high-pressure pump 5, in particular the pumping station 17.
• the flange 18 comprises a friction bearing designed to support rotatably the shaft 19 (not shown in Figure 2), a connector 25 comprising the choke 12 and suitable for connecting the portion of the feed branch 9 outside the flange 18, a connector 26 and a connector 27 for connecting the portion of the delivery branch 10 outside the flange 18.
• the feed branch 9 extends partly inside the flange 18 along a hole 28 parallel to the plane of the sheet in Figure 2 and a hole 29 perpendicular to the plane of the sheet in Figure 2.
• the delivery branch 10 extends partly inside the flange 18 as far as the connector 26 along a hole 30 parallel to the plane of the sheet in Figure 2 and along a hole 31 perpendicular to the plane of the sheet in Figure 2.
• the holes 30 and 31 are arranged in the vicinity of the connector 26.
• the delivery branch 10 extends partly inside the flange 18 as far as the connector 27 along a hole 32 perpendicular to the plane of the sheet in Figure 2.
• the bypass branch 20 extends entirely inside the flange 18 along holes 33, 34, 35, 36 and 37 which are parallel to the plane of the sheet in Figure 2.
• the hole 28 of the feed branch 9 intersects the hole 33, which intersects the hole
• the holes 35 and 36 house, respectively, the overpressure valve 23 and the bypass valve 24.
• the overpressure valve 23 and the bypass valve 24 are similar and each comprise a shutter 38, a spring 39, a ring 40 provided with a frustoconical seat for supporting the shutter 38, and a ring 41 for supporting the spring 39.
• bypass valve 24 is an overpressure valve mounted in the opposite direction to the overpressure valve 23.
• the holes 28, 30, 33, 34, 35, 36 and 37 are formed by means of drill bits used to bore through lateral surfaces 42 and 43 of the flange 18 and are closed on these lateral surfaces 42 and 43 by means of plugs (not shown in the accompanying figures).
• the flange 18 has holes 44 perpendicular to the plane of the sheet in Figure 1 and used to perform assembly of the flange 18 together with the pump body 16 by means of screws (not shown in the accompanying figures).
• the overpressure valve 23 and the bypass valve 24 may be arranged in the flange 18 in accordance with the requirements of car manufacturing companies and therefore result in a reduction in the number of variants of the pre-feed pump 4.
• the high-pressure pump unit described here may be subject to modifications and variations without departing from the scope of the accompanying claims.
• the pump unit 1 may be defined solely by the pump body 16 of the high-pressure pump 5 and by the flange 18, while the pre-feed pump 4 is connected to the high-pressure pump 5 by external pipes.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40291730

Family Applications (1)

Country Status (8)

Families Citing this family (1)

Citations (3)

Family Cites Families (12)

• 2008
  • 2008-02-29 IT IT000340A patent/ITMI20080340A1/it unknown
• 2009
  • 2009-01-21 RU RU2010139573/06A patent/RU2010139573A/ru not_active Application Discontinuation
  • 2009-01-21 KR KR1020107019035A patent/KR20100123848A/ko not_active Application Discontinuation
  • 2009-01-21 CN CN2009801066395A patent/CN101960136B/zh not_active Expired - Fee Related
  • 2009-01-21 EP EP09714990.0A patent/EP2260201B1/en not_active Not-in-force
  • 2009-01-21 WO PCT/EP2009/050611 patent/WO2009106382A1/en active Application Filing
  • 2009-01-21 JP JP2010548043A patent/JP2011513622A/ja active Pending
  • 2009-01-21 US US12/919,865 patent/US20110011371A1/en not_active Abandoned

Patent Citations (3)

Also Published As

Similar Documents

Legal Events